TWI616416B - High cte opal glass compositions and glass articles comprising the same - Google Patents

Abstract

The invention discloses an opal glass composition and a glass object containing the opal glass composition. In one embodiment, the body of the glass composition comprises 55 mole% to 70 mole% of SiO ₂ and 9 mole% to 15 mole% of Al ₂ O ₃ is formed as a glass network. The glass composition also includes 10 mol% to 15 mol% of an alkali metal oxide M ₂ O, where M is at least one of Na and K. The glass composition also includes 2 mol% to 8 mol% of a divalent oxide RO, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from 8.5 mol% to 16 mol%. The glass composition may also include SnO ₂ as a clarifying agent of 0 mol% to 0.3 mol% and a coloring agent of about 0 mol% to about 6 mol%. The glass composition is free of As and As-containing compounds.

Description

High CTE opalescent glass composition and glass object containing same [Cross Reference of Related Applications]

This application claims priority right of US Provisional Application No. 61 / 604,862, filed on February 29, 2012 in accordance with the Patent Law. The content of this application serves as the basis for this application, and the entire content of this application Incorporated herein by reference.

This specification relates generally to glass compositions, and more specifically, to opalescent glass compositions having a relatively high average CTE, and glass articles containing the high CTE opalescent glass composition.

Glass objects formed from opal glass compositions are generally optically opaque. It is believed that the opaque nature of glass is at least partly due to phase separation, which occurs in the glass due to the opacifying agent in the glass composition. This opalescent glass has been used to improve the appearance of a variety of consumer products, such as tableware.

In addition, glass objects (such as glass panels) can be incorporated into consumer products (such as mobile phones) Sub-devices, electrical appliances, etc.). These glass objects must be strong enough to withstand frequent contact without damage. For example, glass objects can be incorporated into portable electronic devices, such as mobile phones, personal media players and tablets, or glass objects can be used as tableware. Glass objects may be easily damaged during transport and / or use of the associated device. Therefore, there is a need to increase the strength of glass objects used in consumer products to resist the inevitable contact and impact that may occur during the use and / or transportation of the items.

The unique appearance of opal glass makes opal glass an attractive option for improving the appearance of consumer products containing glass objects. However, opalescent glass in such items must be strong enough to withstand the rigors of everyday use. Therefore, there is a need for an alternative opalescent glass composition and a glass article containing the alternative opalescent glass composition, which can be used to form a mechanically strong glass object.

According to one embodiment, the glass composition may comprise a body of about 55 mole% to about 70 mole% of SiO ₂ and about 9 mole percent to about 15 mole% of Al ₂ O ₃ as a glass network forming. The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds.

In one set of embodiments, the glass article includes a glass core layer disposed between a first glass cladding layer and a second glass cladding layer. In some of these embodiments, the core glass may have a first surface and a second surface opposite to the first surface, wherein the first glass cladding layer may be fused to the first surface of the glass core layer, and the first The two glass cladding layers can be fused to the second surface of the glass core layer. In other embodiments, the first diffusion glass layer may be disposed between the glass core layer and the first glass cladding layer; in addition, the second diffusion glass layer may be disposed between the glass core layer and the second glass cladding layer; The iso-diffusion layer may be formed, for example, during a melt forming process. The glass core layer is formed of an opalescent glass composition, which may include about 55 mol% to about 70 mol% of SiO ₂ and about 9 mol% to about 15 mol as a glass network forming body. % Of Al ₂ O ₃ . Glass compositions may also include from about 10 mole% to about 15 mole% of M ₂ O, where M is Na and K in the Department of at least one. The glass network may also include about 2 mol% to about 8 mol% of divalent oxide RO, where R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ from about 0 mole% to about 0.3 mole%. The glass composition may be free of As and As-containing compounds.

Additional features and advantages of the glass composition and the glass object formed from the glass composition will be stated in the following embodiments, and through their description, those skilled in the art will obviously part of these features and advantages, or by practicing this document The described embodiments (including the following embodiments, patent application scope, and accompanying drawings) recognize some of these features and advantages.

It should be understood that both the above general description and the following implementations describe various embodiments and are intended to provide an overview or framework to understand the nature and characteristics of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and the accompanying drawings are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments described herein, and together with the description serve to explain the principles and operation of the claimed subject matter.

100‧‧‧ glass objects

102‧‧‧glass core layer

104a‧‧‧First glass coating

104b‧‧‧Second glass cladding

200‧‧‧Laminated Melt Stretching Equipment

202‧‧‧Isostatic pressure tube

204‧‧‧ Lower isostatic pressure tube

206‧‧‧Glass coating composition

208‧‧‧glass core composition

210‧‧‧slot

212‧‧‧slot

216‧‧‧outer shaped surface

218‧‧‧outer shaped surface

220‧‧‧ root

222‧‧‧outer shaped surface

224‧‧‧outer shaped surface

FIG. 1 schematically illustrates a cross-section of a laminated glass article according to one or more embodiments illustrated and described herein; and Fig. 2 schematically illustrates a melt drawing process for making the glass article of Fig. 1.

Reference will now be made in detail to examples of glass compositions having high average thermal expansion coefficients and glass objects containing such glass compositions, and examples of these embodiments are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The glass composition described herein generally has a relatively high average thermal expansion coefficient, and the glass composition itself can be used with a glass cladding composition having a relatively low average thermal expansion coefficient to produce a laminated glass article, the layer Pressed glass objects are compressed under pressure without ion exchange or thermal tempering. In one embodiment, the glass composition may comprise as the glass network formers of about 55 mole% to about 70 mole% of SiO ₂ and about 9 mole percent to about 15 mole% of Al ₂ O _3. The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. Various embodiments of the glass composition and glass objects formed from the glass composition will be described in more detail herein with reference to the accompanying drawings.

As used herein, the term "liquidus viscosity" refers to the shear viscosity of a glass composition at the liquidus temperature of the glass composition.

As used herein, the term "liquidus temperature" refers to the highest temperature at which an anti-glass effect occurs in a glass composition.

As used herein, the term "CTE" refers to a temperature from about 20 ° C to about 300 ° C The coefficient of thermal expansion of the glass composition that takes the average value within the range.

When used to describe the absence of a specific oxide component in the glass composition, the term "substantially free" means that the component is present in the glass composition as an impurity in a trace amount of less than 1 mol%.

In the examples of glass compositions described herein, unless otherwise stated, the concentrations of the constituents (eg, SiO ₂ , Al ₂ O _3, etc.) are given as mole percentages (mole%) based on oxides .

In the examples of the glass composition described herein, SiO ₂ is the largest component of the composition, and likewise, SiO ₂ is the main component of the glass network. When the concentration of SiO ₂ in the glass composition is low (that is, less than about 55 mol%), the chemical durability of the synthetic glass is low. In addition, the liquidus viscosity of synthetic glass may also be low, making the glass unsuitable for fusion molding, such as using a melt down process and / or a melt coating method. However, if the concentration of SiO ₂ in the glass composition is too high (that is, higher than about 70 mole%), the higher concentration of SiO ₂ increases the difficulty of melting the glass, which adversely affects the glass Formability, and therefore the formability of the glass composition may be reduced. The embodiments herein described embodiment, the glass composition substantially contains SiO _2, the SiO ₂ concentration of greater than or equal to about 55 mole% and less than or equal to about 70 mole% to facilitate the formation of a molten glass composition. In some embodiments, the concentration of SiO ₂ in the glass composition is higher than or equal to about 58 mole% and lower than or equal to about 64 mole%. In other embodiments, the concentration of SiO ₂ in the glass composition is higher than or equal to about 60 mole% and lower than or equal to about 64 mole%. In some other embodiments, the glass composition comprises SiO ₂ , the concentration of the SiO ₂ being higher than or equal to about 62 mol% and lower than or equal to about 64 mol%.

The glass compositions described herein also include Al ₂ O ₃ . Al ₂ O _{3 is} used as a glass network former, similar to SiO ₂ . Similar to SiO ₂ , due to the tetrahedral coordination of Al ₂ O ₃ in the glass melt formed from the glass composition, the Al ₂ O ₃ increases the viscosity of the glass composition. Al ₂ O ₃ also improves the chemical durability of the glass and improves the degree to which the strength of the glass can be increased. In particular, Al ₂ O ₃ also increases the strain point of the glass, thereby increasing the temperature at which compressive stress is generated in the glass due to glass cooling, and Al ₂ O ₃ also increases the amount of stress that can be generated in the glass.

In the examples of glass compositions described herein, the concentration of Al ₂ O ₃ is substantially less than or equal to about 15 mole%. For example, in some embodiments, the concentration of Al ₂ O ₃ in the glass composition is higher than or equal to about 9 mole% and lower than or equal to about 15 mole%. In some embodiments, the Al ₂ O ₃ concentration in the glass composition may be higher than or equal to about 9 mole% and lower than or equal to about 13 mole%. In some embodiments, the concentration of Al ₂ O ₃ in the glass composition may be higher than or equal to about 10 mole% and lower than or equal to about 12 mole%.

The glass composition may also include an alkali metal oxide M ₂ O, where M is at least one of Na and K. Therefore, it should be understood that the glass composition described herein may include K ₂ O, Na ₂ O, or a combination of Na ₂ O and K ₂ O. In some embodiments, the alkali metal oxide M ₂ O present in the glass composition consists only of Na ₂ O. The addition of an alkali metal oxide to the glass composition increases the average thermal expansion coefficient of the synthetic glass. The alkali metal oxide also lowers the liquidus temperature of the glass, thereby improving the formability of the glass. However, in the embodiment where the glass composition is used to form a glass core layer of a laminated glass article, the alkali metal oxide present in the composition can promote ion exchange, and the ion exchange strengthens the glass core layer and melts the glass core layer. Interface between glass cladding layers.

In the examples described herein, the total concentration of the alkali metal oxide M ₂ O in the glass composition is substantially less than about 15 mole%. For example, in some embodiments, the concentration of M ₂ O in the glass composition is higher than or equal to about 10 mole% and lower than or equal to about 15 mole%. In some other embodiments, the total concentration of M ₂ O is higher than or equal to about 10 mole% and lower than or equal to about 12 mole%. In other embodiments, the concentration of M ₂ O is higher than or equal to about 11 mole% and lower than or equal to about 13 mole%.

As described above, the alkali metal oxide M ₂ O may include Na ₂ O, K ₂ O, or a combination of Na ₂ O and K ₂ O. Na ₂ O may be present in the glass composition at a concentration higher than or equal to about 5 mole% and lower than or equal to about 15 mole%. In some embodiments, the Na ₂ O concentration may be higher than or equal to about 7 mole% and lower than or equal to about 13 mole%. In some other embodiments, the Na ₂ O concentration may be higher than or equal to about 9 mole% and lower than or equal to about 13 mole%. When K ₂ O is present in the glass composition, K ₂ O may be present at a concentration higher than or equal to about 2 mol% and lower than or equal to about 7 mol%. In some embodiments, K ₂ O may be present in the glass composition at a concentration from about 3 mole% to about 5 mole%. Adding K ₂ O as a substitute for Na ₂ O increases the CTE of the glass composition and lowers the liquidus temperature.

The glass composition described herein may further include a divalent oxide RO, wherein R is at least one of Zn, Ca, and Mg. Therefore, it should be understood that the glass composition may include ZnO, CaO, MgO, or a combination of ZnO, CaO, and MgO. In some embodiments, the divalent oxide RO present in the glass composition consists of only one of ZnO, CaO, or MgO. For example, in some embodiments, the divalent oxide RO consists only of ZnO. The divalent oxide improves the melting characteristics of the glass composition by increasing the liquidus viscosity of the glass composition. The liquidus viscosity of the glass composition can in turn improve the formability of the glass composition. Although slightly inferior to alkali metal oxides, divalent oxides also increase the average thermal expansion coefficient of glass compositions. In detail, the divalent oxides CaO and MgO (ie, alkaline earth metal oxides) increase the average thermal expansion coefficient of the glass composition and also increase the liquidus viscosity.

In the embodiments described herein, the total concentration of the divalent oxide RO (ie, the total concentration of MgO, CaO, and / or ZnO) is greater than or equal to about 2 mole% and less than or equal to about 8 mole %. In some of these embodiments, the total concentration of the divalent oxide RO is less than or equal to about 5.5 mole%, such as when the total concentration of the divalent oxide is greater than or equal to about 2 mole% and less than Or equal to about 5.5 mole%.

As described above, the divalent oxide RO may include MgO, CaO, ZnO, or a combination of MgO, CaO, and ZnO. MgO may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 4.0 mole%. In some embodiments, the concentration of MgO may be higher than or equal to about 0 mole% and lower than or equal to about 3.5 mole%. CaO may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 4 mole%. In some embodiments, CaO may be present in the glass composition at a concentration from about 0 mole% to about 3.5 mole%. ZnO may be present in the glass composition at a concentration higher than or equal to about 2 mole% and lower than or equal to about 8 mole%. In some embodiments, ZnO may be present in the glass composition at a concentration of greater than or equal to about 3 mole% and less than or equal to about 8 mole%. In some other embodiments, ZnO may be present in the glass composition at a concentration of greater than or equal to about 5.5 mole% and less than or equal to about 8 mole%.

The glass compositions described in this document also include a fluoride ion (F ^-). F ^- Used as a milky agent which changes the glass from transparent or translucent to opaque. Although unwilling to be bound by theory, it is believed that this transition from transparent or translucent to opaque glass is due to the phase separation in the glass substrate, which is due to the presence of fluorine. In the embodiments described herein, this conversion occurs when the glass composition is formed into a glass object (ie, "in the drawing process"), or the conversion occurs by applying a heat treatment to the glass object after forming. From now on, glass means opal glass. In the embodiments described herein, fluorine may be introduced into the glass by a fluorine precursor added to the glass batch, the fluorine precursor including (but not limited to) CaF ₂ , Na ₂ SiF ₆ , AlF ₃ or Na ₃ AlF ₆ .

In the embodiment described, the ingredients of the glass composition embodiments herein include F ^-, F ^- concentration of greater than or equal to about 8.5 mole% and less than or equal to about 16 mole%. In some embodiments, F ^- the concentration may be greater than or equal to about 12.5 mole%, and may be less than or equal to about 16 mole%. In some embodiments, the composition of the glass F ^- The concentration may be greater than or equal to about 10.5 mole% and less than or equal to about 16 mole%, or even less than or equal to about 14 mole%.

In some embodiments, the glass composition may further include a colorant. A colorant is added to the glass composition to impart color to opalescent glass after a transition from transparent or translucent to opaque occurs. For example, in an embodiment that is converted to opaque to produce a milky glass, a colorant is added to the glass composition to change the color of the opaque glass to the color of the colorant. Suitable colorants include, but are not limited to, Fe ₂ O ₃ , Cr ₂ O ₃ , Co ₃ O ₄ , CuO, Au, and V ₂ O ₅ , each of which can impart a unique color to opalescent glass.

In the embodiments described herein, the colorant may be present in the glass composition at a concentration of greater than or equal to about 0 mole% (i.e., no colorant) to a concentration of less than or equal to about 6 mole%. . In some embodiments, the colorant may have a concentration greater than or equal to about 0 mole% to less than or equal to about 5 mole%. In some other embodiments, the concentration of the coloring agent in the glass composition may be higher than or equal to about 0 mole% and lower than or equal to about 2 mole%, or even lower than or equal to about 1 mole%.

In an example of the colorant-based Fe ₂ O ₃ , Fe ₂ O ₃ may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 3 mole%. In the example of the colorant-based Cr ₂ O ₃ , Cr ₂ O ₃ may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 2 mole%. In an example of the colorant-based Co ₃ O ₄ , Co ₃ O ₄ may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 1 mole%. In an example of the colorant-based CuO, CuO may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 3 mole%. In an example of the colorant-based Au, Au may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 1 mole%. In the example of the colorant system V ₂ O ₅ , V ₂ O ₅ may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 4 mole%.

In some embodiments of the glass composition described herein, the glass composition may further include B ₂ O ₃ . Similar to SiO ₂ and Al ₂ O ₃ , B ₂ O ₃ helps to form a glass network. B ₂ O _{3 is} added to the glass composition to reduce the viscosity and liquidus temperature of the glass composition. In particular, depending on the specific composition of the glass, each 1 mole% increase in the concentration of B ₂ O ₃ can reduce the temperature required to obtain an equivalent viscosity by 10 ° C. to 14 ° C. However, each mole% of B ₂ O ₃ can decrease the liquidus temperature of the glass composition by 18 ° C to 22 ° C. In this regard, B ₂ O ₃ decreases the liquidus temperature of the glass composition faster than the liquidus viscosity of the glass composition, and then effectively increases the liquidus viscosity. B ₂ O ₃ can also be added to the glass composition to soften the glass network. Therefore, B ₂ O ₃ can be used to improve the melting performance of the glass composition. Adding B ₂ O ₃ to the glass composition also reduces the Young's modulus of the glass composition and improves the intrinsic damage resistance of the glass.

In the described embodiment, B ₂ O ₃ may be present in the glass composition at a concentration higher than or equal to about 0 mole% and lower than or equal to about 5 mole%. For example, in some embodiments, the glass composition may comprise greater than or equal to about 0 mole% of B ₂ O ₃ and less than or equal to about 3 mole% of B ₂ O _3.

The glass compositions described herein may optionally include a fining agent. For example, the fining agent may be SnO ₂ . The fining agent may be present in the glass composition at a concentration of greater than or equal to about 0 mole% and less than or equal to about 0.5 mole%. In some embodiments, the fining agent may be present in the glass composition at a concentration of greater than or equal to about 0 mole% and less than or equal to about 0.2 mole% or even less than or equal to about 0.15 mole%. Although examples of the glass composition described herein may include a fining agent, the glass composition is substantially free of arsenic and / or antimony and compounds including the above. In this regard, it should be understood that the glass compositions described herein are substantially free of fining agents such as As ₂ O ₃ and Sb ₂ O ₃ .

The glass compositions described herein generally have an average coefficient of thermal expansion (CTE) that is greater than or equal to about 75x10 ^-7 / ° C in a range from 20 ° C to 300 ° C. In some embodiments, the average CTE of the glass composition may be greater than or equal to about 80 x 10 ^-7 / ° C in a range from 20 ° C to 300 ° C. In other embodiments, the average CTE of the glass composition averaged in a range from 20 ° C to 300 ° C may be greater than or equal to about 85x10 ^-7 / ° C. The relatively high average CTE value of the glass composition is at least partly due to the concentration of alkali metal oxides in the glass. These relatively high average CTEs make the glass composition particularly suitable for use as a glass core layer for melt-formed laminated glass objects. In particular, when a glass cladding layer with a low average CTE and a glass core layer with a higher average CTE are paired during the melting layer pressing process, the difference in the average CTE of the glass core layer and the glass cladding layer causes the glass to cool down after cooling. A compressive stress is formed in the cladding layer. Therefore, the glass compositions described herein can be used to form reinforced laminated glass articles.

In addition, the glass composition described herein has a liquidus viscosity and a liquidus temperature suitable for, for example, melt forming by a melt down process and / or a melt coating method. In particular, the glass compositions described herein have a liquidus viscosity of greater than or equal to about 35 kilopoises. In some embodiments, the liquidus viscosity is greater than or equal to 100 kilopoises, or even greater than or equal to 200 kilopoises. The liquidus temperature in the glass composition is lower than or equal to about 1400 ° C. In some embodiments, the liquidus temperature is lower than or equal to 1350 ° C, or even lower than or equal to 1300 ° C.

From the foregoing, it should be understood that various examples of high average CTE opalescent glass compositions are disclosed herein. In the first exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In the second exemplary embodiment, the glass composition may include SiO ₂ from about 58 mol% to about 64 mol% as a glass network forming body and from about 10 mol% to about 12 mol%. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 11 mol% to about 13 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 5.5 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 12.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In a third exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 2 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In the fourth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The colorant may be selected from the group consisting of Fe ₂ O ₃ , Cr ₂ O ₃ , CO ₃ O ₄ , CuO, Au, and V ₂ O ₅ . The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In a fifth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . Glass compositions may also include from about 10 mole% to about 15 mole% of alkali metal oxide M ₂ O, where M series Na. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In a sixth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition may also include B ₂ O ₃ . The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In an eighth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% as a glass network forming body and from about 9 mol% to about 15 mol%. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 10.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In a ninth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, wherein R is at least one of Zn, Ca, and Mg. As a milky agent, the glass composition may also include F ^- from about 12.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In the tenth exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 8 mol%, where R is Zn. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

In the eleventh exemplary embodiment, the glass composition may include SiO ₂ from about 55 mol% to about 70 mol% and from about 9 mol% to about 15 mol% as a glass network forming body. Of Al ₂ O ₃ . The glass composition may also include an alkali metal oxide M ₂ O from about 10 mol% to about 15 mol%, where M is at least one of Na and K. The glass composition may also include a divalent oxide RO from about 2 mol% to about 5.5 mol%, where R is Zn. As a milky agent, the glass composition may also include F ^- from about 8.5 mol% to about 16 mol%. The glass composition may also include SnO ₂ as a fining agent from about 0 mole% to about 0.3 mole% and a coloring agent from about 0 mole% to about 6 mole%. The glass composition is free of As and As-containing compounds. The glass composition may have an average CTE greater than or equal to 75x10 ^-7 / ° C or even 85x10 ^-7 / ° C.

While reference to various compositions of the glass composition of each component (such as SiO _2, Al ₂ O _3, etc.) in the specific composition range described above exemplary glass composition, it is to be understood, as described above, each of the components Each of the composition ranges may include a narrower composition range for one or more of the constituents. In addition, it should also be understood that these narrower ranges of the constituents and / or the relationships between the various constituents can be incorporated into any of the embodiments of the glass composition described herein to produce the desired characteristics. glass.

Referring now to FIG. 1, the glass composition described herein can be used to form glass objects, such as the laminated glass object 100 schematically illustrated in a cross-sectional view in FIG. 1. The laminated glass article 100 generally includes a glass core layer 102 and a pair of glass cladding layers 104a and 104b. Due to the relatively high average thermal expansion coefficient, the glass composition described herein is particularly suitable for use as a glass core layer and will be described in more detail herein.

FIG. 1 illustrates a glass core layer 102 which is illustrated as including a first surface and a second surface opposite to the first surface. The first glass cladding layer 104a is fused to the first surface of the glass core layer 102, and the second glass cladding layer 104b Fused to the second surface of the glass core layer 102. The glass cladding layer 104a and the glass cladding layer 104b are fused to the glass core layer 102, and no additional materials (such as an adhesive, Coating or etc.). Therefore, the first surface of the glass core layer is directly adjacent to the first glass cladding layer, and the second surface of the glass core layer is directly adjacent to the second glass cladding layer. In some embodiments, the glass core layer 102, the glass cladding layer 104a, and the glass cladding layer 104b are formed by a melt coating method. A diffusion layer (not shown) may be formed between the glass core layer 102 and the glass cladding layer 104a, or between the glass core layer 102 and the glass cladding layer 104b, or both. In this case, the average thermal expansion coefficient of the first diffusion layer has a value between the average core thermal expansion coefficient of the glass core layer 102 and the average thermal expansion coefficient of the first cladding layer, or the second diffusion layer The average thermal expansion coefficient of the diffusion layer has a value between the average thermal expansion coefficient of the glass core layer 102 and the average thermal expansion coefficient of the second cladding layer.

In the embodiment of the laminated glass article 100 described herein, the glass core layer 102 is formed of a first glass composition, the first glass composition has an average core thermal expansion coefficient CTE _core , and the glass cladding layer 104a, the glass envelope The cladding layer 104b is formed of a different second glass composition having an average thermal expansion coefficient CTE _clad . The CTE _{core is} larger than the CTE _clad , which causes the glass cladding layer 104a and the glass cladding layer 104b to be compressed and compressed without ion exchange or thermal tempering.

In particular, the glass article 100 described herein may be formed by a melt coating method such as that described in US Patent No. 4,214,886, which is incorporated herein by reference. Referring to FIG. 2 by way of example, a lamination melt stretching apparatus 200 for forming a laminated glass article includes an upper isostatic pipe 202 positioned above the lower isostatic pipe 204 . The upper isostatic tube 202 includes a tank 210 into which the molten glass coating composition 206 is fed from a melter (not shown). Similarly, the lower isostatic pressure tube 204 includes a groove 212 into which the molten glass core composition 208 is fed from a melter (not shown). In the embodiment described herein, the molten glass core composition 208 has a larger average thermal expansion coefficient CTE _core than the average thermal expansion coefficient CTE _{clad of the} molten glass cladding composition 206.

As the molten glass core composition 208 fills the groove 212, the glass core composition 208 overflows the groove 212 and flows through the outer forming surface 216 and the outer forming surface 218 of the lower isostatic tube 204. The outer forming surface 216 and the outer forming surface 218 of the lower isostatic tube 204 converge at the root 220. Therefore, the molten glass core composition 208 flowing through the outer forming surface 216 and the outer forming surface 218 is reassembled at the root 220 of the lower isostatic tube 204 to form the glass core layer 102 of the laminated glass object.

At the same time, the molten glass coating composition 206 overflows the groove 210 formed in the upper isostatic tube 202 and flows through the outer forming surface 222 and the outer forming surface 224 of the upper isostatic tube 202. The molten glass coating composition 206 is deflected outward by the upper isostatic tube 202 so that the molten glass coating composition 206 flows around the lower isostatic tube 204 and flows through the lower isostatic tube The outer forming surface 216 and the molten glass core composition 208 of the outer forming surface 218 are in contact, and then melt to the molten glass core composition and form a glass cladding layer 104 a and a glass cladding layer 104 b surrounding the glass core layer 102.

As described above, the molten glass core composition 208 generally has a larger average thermal expansion coefficient CTE _core than the average thermal expansion coefficient CTE _{clad of the} molten glass cladding composition 206. Therefore, as the glass core layer 102, the glass cladding layer 104a, and the glass cladding layer 104b cool, the difference in the average thermal expansion coefficients of the glass core layer 102, the glass cladding layer 104a, and the glass cladding layer 104b results in the glass cladding layer. 104a, a compressive stress is generated in the glass cladding layer 104b. In the absence of ion exchange or thermal tempering, the compressive stress increases the strength of the resulting laminated glass article.

Referring again to the laminated glass article 100 illustrated in FIG. 1, the glass core layer 102 of the laminated glass article is formed of a glass composition having a relatively high average thermal expansion coefficient, such as described herein having a greater than Or glass composition with an average thermal expansion coefficient of 75x10 ^-7 / ℃.

For example, in one embodiment, the glass core layer is formed of a glass composition having a high average CTE, such as the glass composition described herein, the glass composition comprising from about 55 mol% to About 70 mol% SiO ₂ , from about 9 mol% to about 15 mol% Al ₂ O ₃ , from about 10 mol% to about 15 mol% alkali metal oxide M ₂ O (wherein, M is at least one of Na and K), divalent oxide RO (of which R is at least one of Zn, Ca, and Mg) from about 2 mol% to about 8 mol%, from about 8.5 mole% to about 16 mole% of F ^-, from about 0 mole% to about 0.3 mole% of SnO ₂ and from about 0 mole% to about 6 mole% of a colorant, wherein the glass composition is not As-containing and As-containing compounds.

In another embodiment, the core layer may be a glass having a glass composition of a high average CTE is formed, the glass composition includes from about 58 mole% to about 64 mole% of SiO _2, from about 10 mole% to about 12 mol% Al ₂ O ₃ , from about 11 mol% to about 13 mol% alkali metal oxide M ₂ O, from about 2 mol% to about 5.5 mol% RO, from about 12.5 mol F ^- about 16 mol%, SnO ₂ from about 0 mol% to about 0.3 mol%, and coloring agent from about 0 mol% to about 6 mol%, wherein the glass composition does not contain As and As-containing compounds.

Although specific glass compositions have been described herein for use as the glass core layer 102, it is understood that any glass composition described herein can be used to form the glass core layer 102 of the laminated glass article 100.

In addition, although it has been described above that the glass core layer 102 of the glass laminate structure is formed of a glass composition having a relatively high average thermal expansion coefficient, the glass cladding layer 104a and the glass cladding layer 104b of the glass article 100 A glass composition having an average coefficient of thermal expansion is formed to promote the generation of compressive stress in the cladding layer after cooling the laminated glass object after the melt forming. For example, the glass cladding can be formed from a glass composition such as co-pending U.S. patent application entitled "Low CTE Alkali-Free Boro Aluminosilcate Glass Compositions and Glass Articles Comprising the Same" The composition described in Case No. 61 / 604,839 has an average thermal expansion coefficient averaged over a temperature range from 20 ° C to 300 ° C and less than or equal to 40x10 ^-7 / ° C. For example, the glass cladding layer may be formed of a glass composition including: SiO ₂ from about 60 mol% to about 66 mol%, and Al ₂ from about 7 mol% to about 10 mol%. O ₃ , B ₂ O ₃ from about 14 mol% to about 18 mol%, and alkaline earth metal oxides from about 9 mol% to about 16 mol%, wherein the alkaline earth metal oxide contains at least CaO and CaO It is present in the glass composition at a concentration of from about 3 mol% to about 12 mol%, and the glass composition is substantially free of alkali metals and compounds containing alkali metals.

In another embodiment, the glass cladding layer may be formed from a glass composition described in a co-pending agreement with Corning Corporation entitled "Low CTE, Ion-Exchangeable Glass Compositions and Glass Articles Comprising the Same" In US Patent Application No. 61 / 604,833, the composition has an average thermal expansion coefficient averaged over a temperature range from 20 ° C to 300 ° C and less than or equal to 55x10 ^-7 / ° C. For example, a glass coating layer may comprise a glass of the following composition is formed by: from about 65 mole% to about 70 mole% of SiO _2, from about 9 to about 14 mole% of Al ₂ mole% O ₃ , from about 0 mole% to about 11 mole% of B ₂ O ₃ , from about 5 mole% to less than 10 mole% of alkali metal oxide R ₂ O (wherein R is Li, Na and K At least one of them) and a divalent oxide MO from about 3 mol% to about 11 mol%, wherein M is at least one of Mg, Ca, Ba, and Zn. In this embodiment, the glass coating can be ion-exchanged to further strengthen the glass object.

It should be understood that other glass compositions may also be used to form the glass of the laminated glass object 100. As long as the average thermal expansion coefficient of the glass cladding layer 104a and the glass cladding layer 104b is smaller than the average thermal expansion coefficient of the glass core layer 102, the glass cladding layer 104a and the glass cladding layer 104b.

Examples

Examples of the glass composition described herein will be further illustrated by the following examples.

A plurality of exemplary glass compositions were prepared according to the ingredient compositions listed in Tables 1 to 4 below. In each of these examples, F ^- was introduced into the glass batch as Na ₂ SiF ₆ . The ingredients of the oxide composition are mixed, melted and formed into a glass plate. Tables 1 to 4 report the milky state of the glass after forming and / or annealing at 700 ° C. For Examples 19 to 24, the characteristics of the glass melt (ie, liquidus temperature, annealing point, etc.) were measured, and the results are reported in Table 3. For Example 20, Example 23, and Example 24, collect high-temperature viscosity data and determine the high-temperature viscosity parameter A, high-temperature viscosity parameter B, and high-temperature viscosity parameter T ₀ using the Fulcher equation: Logη = A + B / ( T - T ₀ ) where Is the shear viscosity, T is the Celsius temperature, and A, B and T ₀ are constants for each specific composition.

Referring to Table 1, Examples C1 to C6 did not form opalescent glass during stretching or after heat treatment after stretching. Therefore, Examples C1 to C6 are provided for comparison purposes. Comparative Example C1, Comparative Example C2, and Comparative Example C5 were used to evaluate the substitution effect of Al ₂ O ₃ to SiO ₂ . Examples C3 and C4 were used to evaluate the substitution effect of fluorine to Na ₂ O in the glass composition. Inventive Examples 7 to 9 were used to evaluate the substitution effects of Al ₂ O ₃ to SiO ₂ and fluorine to Na ₂ O. These glass compositions are at least partially milk-whitened during stretching.

Referring to Table 2, Inventive Examples 10 to 16 are based on the glass compositions of Inventive Example 8 and Inventive Example 9. Examples C17 to C18 are not milk whitened and are provided for comparison purposes. Inventive Example 10 and Inventive Example 11 were used to evaluate the substitution effect of CaO and MgO for ZnO. Each of these glasses is milky at least partially. Inventive Example 12 indicates that the replacement of fluorine with B ₂ O ₃ yields a good opal glass. Inventive Examples Inventive Examples 13 and 14 indicate alternative Na ₂ O K ₂ O is also output with a good opal glass. Inventive Example 15 and Inventive Example 16 were used to evaluate the alternative effects of Al ₂ O ₃ to SiO ₂ (Example 15) and fluorine to Na ₂ O (Example 16). Both of the above examples produced good opal glass. The observation of milk whitening was performed after annealing treatment at 700 ° C.

Referring to Table 3, Examples 19 to 24 are inventive example 8 (comparative example 19), inventive example 10 (inventive example 20), inventive example 12 (comparative example 21), and inventive example 14 (comparative example 22) Scale-up versions of Inventive Example 15 (Inventive Example 23) and a combination of Inventive Example 10 and Inventive Example 14 (Inventive Example 24). Inventive Example 20, Inventive Example 23, and Inventive Example 24 produced good opalescent glass, while Comparative Example 19, Comparative Example 21, and Comparative Example 22 produced only partially opalized glass. It is believed that the lack of opalescence in these glasses is due to the loss of fluorine upon evaporation during remelting of the composition. Therefore, although these compositions are properly formulated to produce opalescent glass (as indicated by Inventive Example 8, Inventive Example 10, Inventive Example 12, Inventive Example 14, and Inventive Example 15), the fluorine content during processing is The loss of phase reduces phase separation, which is necessary for milk whitening. The observation of milk whitening was performed after the annealing treatment at 700 ° C.

Referring to Table 4, Examples 25 to 33 were used to evaluate the effect of different colorants added to the glass batch. As shown in Examples 25 to 30, adding Fe ₂ O ₃ , Cr ₂ O ₃ , Co ₃ O ₄ , CuO, Au, and V ₂ O ₅ produced colored milk glass. The observation of milk whitening was performed after the annealing treatment at 700 ° C.

It should now be understood that the opalescent glass composition described herein has a relatively high average thermal expansion coefficient. In this regard, the glass composition described herein is particularly suitable for use with glass compositions having a relatively low average coefficient of thermal expansion to form a compressed ground by a melt coating method. Laminated glass objects. The opaque nature of these glass objects makes them suitable for use in utensils, tabletops, home appliance covers, and back panels of handheld electronic devices.

It should also be understood that the characteristics of the glass compositions described herein (e.g., liquidus viscosity, liquidus temperature, etc.) make these glass compositions very suitable for use in melt forming processes, such as a melt down process or a melt coating process .

Although specific references have been made herein to the use of glass compositions as the core layer of a laminated glass article, it should be understood that these glass compositions can also be used to independently form glass articles (i.e., unlaminated glass) Objects), such as, for example, the back panel of an electronic device.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, if modifications and changes to the various embodiments described herein are within the scope of the appended claims and their equivalents, this description is intended to cover such modifications and changes.

100‧‧‧ glass objects

102‧‧‧glass core layer

104a‧‧‧First glass coating

104b‧‧‧Second glass cladding

Claims (32)

A glass composition, the glass composition comprising: from about 55 mole% to about 70 mole% of SiO _2; from about 9 to about 15 mole% mole% of Al ₂ O _3; from about 10 mole % To about 15 mole% of alkali metal oxide M ₂ O, where M is at least one of Na or K; from about 2 mole% to about 5.5 mole% of divalent oxide RO, where R is At least one of Zn, Ca, or Mg; F ^- from about 8.5 mole% to about 16 mole%; SnO ₂ from 0 mole% to about 0.5 mole%; and from 0 mole% to about 6 mol% coloring agent, wherein the glass composition does not contain As and As-containing compounds, and the glass composition is spontaneously milked during forming or milked by a heat treatment after forming. The requested item of a glass composition according to 1, wherein the glass composition comprises: from about 58 mole% to about 64 mole% of SiO _2; from about 10 mole% to about 12 mole% of Al ₂ O ₃ ; M ₂ O from about 11 mol% to about 13 mol%; and F ^- greater than or equal to about 12.5 mol%. The glass composition according to claim 1, wherein a concentration of one of the colorants is less than or equal to 2 mole%. The glass composition according to claim 1, wherein the colorant is selected from the group consisting of Fe ₂ O ₃ , Cr ₂ O ₃ , Co ₃ O ₄ , CuO, Au, and V ₂ O ₅ . The glass composition according to claim 1, wherein M is Na. The glass composition according to claim 1, further comprising B ₂ O ₃ . The glass composition according to claim 1, wherein the glass composition contains F ^- greater than or equal to about 10.5 mole%. The glass composition according to claim 1, wherein the glass composition contains F ^- greater than or equal to about 12.5 mole%. The glass composition according to claim 1, wherein R is Zn. The glass composition according to claim 1, wherein the glass composition is free of P ₂ O ₅ and PbO. The glass composition according to claim 1, wherein the glass composition is milk-whitened, and the milk-whitening is a result of phase separation. A glass object includes a glass core layer disposed between a first glass coating layer and a second glass coating layer, wherein the glass core layer is formed of a milky glass composition, and the milky white a glass composition comprising: from about 55 mole% to about 70 mole% of SiO _2; from about 9 to about 15 mole% mole% of Al ₂ O _3; from about 10 mole% to about 15 mole % Of M ₂ O, where M is at least one of Na or K; from about 2 mole% to about 5.5 mole% of divalent oxide RO, where R is at least one of Zn, Ca, or Mg ; F ^- from about 8.5 mol% to about 16 mol%; and SnO ₂ from 0 mol% to about 0.5 mol%, wherein the opal glass composition does not contain As and As-containing compounds, and the The opalescent glass composition is milked either spontaneously during forming or by a post-forming heat treatment. The glass article according to claim 12, wherein: the glass core layer has an average core thermal expansion coefficient CTE _core ; and the first glass cladding layer and the second glass cladding layer have an average thermal expansion coefficient CTE _clad , the average cladding layer thermal expansion coefficient CTE _{clad is} smaller than the average core thermal expansion coefficient CTE _core . The glass article according to claim 13, wherein the average core thermal expansion coefficient CTE _core , which is an average value in a temperature range from 20 ° C to 300 ° C, is greater than or equal to 75x10 ^-7 / ° C. The glass article according to claim 13, wherein the average core thermal expansion coefficient CTE _core , which is averaged in a temperature range from 20 ° C to 300 ° C, is greater than or equal to 85x10 ^-7 / ° C. The glass article according to claim 12, wherein the first glass coating layer and the second glass coating layer are formed of ion-exchangeable glass. The glass article according to claim 12, wherein the first glass coating layer and the second glass coating layer are compressed under compression. The glass article according to claim 12, wherein the glass core layer further comprises a colorant. The glass article of claim 18, wherein the colorant is present in the glass core layer at a concentration of less than about 6 mole%. The glass article according to claim 18, wherein the colorant is present in the glass core layer at a concentration of less than or equal to 2 mole%. The glass article according to claim 18, wherein the colorant is selected from the group consisting of Fe ₂ O ₃ , Cr ₂ O ₃ , Co ₃ O ₄ , CuO, Au, and V ₂ O ₅ . The glass article of item 12, wherein the request, wherein the glass core layer comprising: from about 58 mole% to about 64 mole% of SiO _2; from about 10 mole% to about 12 mole% of Al ₂ O ₃ ; M ₂ O from about 11 mol% to about 13 mol%; and F ^- greater than or equal to about 12.5 mol%. The glass article according to claim 12, wherein the opalescent glass composition comprises F ^- greater than or equal to about 10.5 mole%. The glass article of claim 12, wherein the opalescent glass composition comprises F ^- greater than or equal to about 12.5 mole%. The glass article according to claim 12, wherein R is Zn. The glass article according to claim 12, wherein the opalescent glass composition does not contain P ₂ O ₅ and PbO. The glass article according to claim 12, wherein the milky glass composition is milk-whitened, and the milk-whitening is a result of phase separation. The glass article according to claim 12, wherein a first surface of the glass core layer is directly adjacent to the first glass cladding layer, and a second surface of the glass core layer is adjacent to the second glass The cladding layers are directly adjacent. The glass article according to claim 28, wherein: a first diffusion layer is disposed between the first glass cladding layer and the glass core layer; and an average diffusion layer thermal expansion coefficient of one of the first diffusion layers has between the average thermal expansion coefficient of the core layer of the core glass of the CTE _core and the cladding layer of the first cladding layer an average value between the coefficients of thermal expansion CTE _clad. The glass article according to claim 29, wherein: a second diffusion layer is disposed between the second glass cladding layer and the glass core layer; and an average diffusion layer thermal expansion coefficient of one of the second diffusion layers has between the average thermal expansion coefficient of the core layer of the core glass CTE _core and the cladding layer of the second cladding layer an average value between the coefficients of thermal expansion CTE _clad. A glass composition according to any one of claims 1 to 11 for use in glass in consumer or commercial electronic devices including LCD displays and LED displays, computer monitors, automatic teller machines (ATMs) Protective cover applications or glass backplane applications; for touch screen applications or touch sensor applications; for portable electronic devices including mobile phones, personal media players and tablets; for optoelectronic applications; for architectural glass Applications; for automotive or vehicle glass applications; or for commercial or home electrical applications. A glass object according to any one of claims 12 to 30 for use in glass protection in consumer or commercial electronic devices including LCD displays and LED displays, computer monitors, automatic teller machines (ATMs) Cover applications or glass backplane applications; for touch screen applications or touch sensor applications; for including mobile phones, personal media players, and tablets Portable electronic devices; for optoelectronic applications; for architectural glass applications; for automotive or vehicle glass applications; or for commercial or home electrical applications.